Field of the Disclosure
The present invention relates generally to semiconductor devices and more specifically to switches including a normally-off device and a normally-on device in a cascode configuration.
Background
Electronic devices use power to operate. Switched mode power converters are commonly used due to their high efficiency, small size, and low weight to power may of today's electronics. Conventional wall sockets provide a high voltage alternating current. In a switching power converter, the high voltage alternating current (ac) input is converted to provide a well-regulated direct current (dc) output through an energy transfer element. The switched mode power converter usually provides output regulation by sensing one or more inputs representative of one or more output quantities and controlling the output in a closed loop. In operation, a switch is utilized to provide the desired output by varying the duty cycle (typically the ratio of the on time of the switch to the total switching period), varying the switching frequency, or varying the number of pulses per unit time of the switch in a switched mode power converter.
Various semiconductor devices may be used for the switch of the switched mode power converter, such as a metal-oxide-semiconductor field-effect transistor (MOSFET), insulated-gate bipolar transistor (IGBT), or a bipolar junction transistor (BJT). These transistors may be fabricated using silicon (Si), silicon carbide (SiC), or gallium nitride (GaN) technologies.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.